Someone online wondered why Truvada isn't protected as a preventive drug under PPACA (as contraceptives and various other things are). Found an interesting article from a year ago on the issue. The article suggests it "being new" factors in, no specific legal barrier as such appears to be present. HIV prevention is discussed in this article. Loads of questions like this will be up in the air during the next four years and POTUS will have a lot of discretion and power to affect the results. Somewhat related on that general topic.